This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A219367 Number of n X 2 arrays of the minimum value of corresponding elements and their horizontal or vertical neighbors in a random, but sorted with lexicographically nondecreasing rows and columns, 0..3 n X 2 array. 2
 4, 13, 60, 193, 514, 1231, 2748, 5802, 11665, 22432, 41419, 73698, 126799, 211612, 343525, 543837, 841488, 1275151, 1895734, 2769343, 3980760, 5637493, 7874458, 10859356, 14798811, 19945338, 26605213, 35147320, 46013053, 59727354, 76910971 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Column 2 of A219373. LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = (1/13440)*n^8 + (1/3360)*n^7 + (1/576)*n^6 + (41/240)*n^5 - (9419/5760)*n^4 + (2009/160)*n^3 - (70291/2016)*n^2 + (42649/840)*n - 29 for n>1. Conjectures from Colin Barker, Mar 11 2018: (Start) G.f.: x*(4 - 23*x + 87*x^2 - 215*x^3 + 349*x^4 - 353*x^5 + 219*x^6 - 84*x^7 + 25*x^8 - 6*x^9) / (1 - x)^9. a(n) = 9*a(n-1) - 36*a(n-2) + 84*a(n-3) - 126*a(n-4) + 126*a(n-5) - 84*a(n-6) + 36*a(n-7) - 9*a(n-8) + a(n-9) for n>9. (End) EXAMPLE Some solutions for n=3: ..0..0....0..0....1..1....2..2....0..0....0..0....2..1....1..0....2..0....2..0 ..0..1....0..1....1..1....2..2....0..0....0..2....1..1....0..0....0..0....0..0 ..2..3....3..1....2..3....2..3....0..1....2..2....1..1....2..0....2..0....3..0 CROSSREFS Cf. A219373. Sequence in context: A317891 A115455 A241470 * A149487 A320359 A057712 Adjacent sequences:  A219364 A219365 A219366 * A219368 A219369 A219370 KEYWORD nonn AUTHOR R. H. Hardin, Nov 19 2012 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified July 19 12:49 EDT 2019. Contains 325159 sequences. (Running on oeis4.)